In a magnetic tape recorder which may store and reproduce information by helical scanning, it is common to provide a cylinder having a rotary head, inclining to a horizontal reference plane (for example, the top surface of a chassis) which is perpendicular to rotational axes of tap reels. When such a cylinder is utilized, a pair of tape pull-out means are required to pull out a tape from a tape cassette and to wind the tape around the cylinder surface for a predetermined angle.
In this connection, it has been known that when a tape is transferred by keeping the tape surfaces orthogonal to a reference plane and at the same time by keeping the tape edges parallel to the reference plane, and is contacted with a cylinder surface which is inclined to said reference plane, the orientation of the surfaces and edges of said tape with respect to the reference plane are varied.
There is a known tape pull-out means which has two guide pins, one is inclined and the other is oriented orthogonal to a reference plane, mounted on a carrier movable between a home position adjacent to a tape reel and a pulled-out position or a loading position adjacent to a cylinder. When a pair of such tape pull-out means are moved at both side of the cylinder, the inclined pins may change the orientation of the surfaces and edges of said tape with respect to the reference plane upstream and downstream of said cylinder so that tape surfaces which are orthogonal to said reference plane are changed into nonorthogonal (in upstream position) or vice versa (downstream) and that tape edges which are parallel to the reference plane are changed into nonparallel (upstream) or vice versa (downstream). When the pull out means are moved, however, the inclined guide pins are contacted with the tape surface and a force to move the tape in the direction of its width is generated. This force may cause a shift of the tape in the direction of its width (i.e. the axial direction of the inclined pin) and in result the movement of the tape away from the pins would occur resulting in the failure of pull out the tape.
A tape pull-out means having a plurality of inclined pins is disclosed in Japanese Unexamined Patent Application Gazette No. 60-253053. The use of a plurality of inclined pins necessitates accurate adjustment of relative inclination between the pins and the associated cylinder in manufacturing and installation. In order to reduce the troublesome adjustment of the relative inclination, it is proposed, in this reference, to form two inclined pins in one block.
However, the tape pull-out means having one or more inclined pins on a movable carrier has a defect to require accurate installation and positioning at their pulled out position, since inaccuracy in installation or positioning may result in inaccuracy in winding the tape on the inclined pin in a predetermined angle, which in turn results in inaccuracy of the angle of the tape surface against a reference plane and inaccuracy of the distance between the tape edges and the reference plane. This problem cannot be solved even if a guide block having one or more inclined pins are fixedly disposed with respect to a cylinder as a stationary guide, since inaccuracy of the pulled-out position of the pull-out pin with respect to the stationary guide may result in inaccuracy of winding the tape on one of said inclined pins of the stationary guide in a predetermined angle.
The solution to this problem is disclosed in the U.S. patent application Ser. No. 154,265 filed on Feb. 10, 1988, now U.S. Pat. No. 4,875,126 by Niro Nakamichi. In this application, there is disclosed a stationary tape guide having a laterally extending guide path, the general contour of which is forwardly convexed, along which at least two straight guide projections inclined to said reference plane and a single straight guide projection extending orthogonal to said reference plane are serially and integrally provided on a guide block. In the preferred embodiments in said application, the tape guide is further provided with means for guiding an upper edge of a tape integrally or detachably therewith.
In the tape guide disclosed in the application, however, the edge guide means could not adjust the level of the edge guide surface with respect to the reference plane. When the securing means required for connecting the tape guide on a magnetic tape recorder is separately provided in addition to the securing means for connecting the detachable edge guide means or means for adjusting the level of the edge guide surface, the structure of the tape guide is too complicated and too large to conform to the requirment to minimize the size of a magnetic tape recorder.